This invention relates to a paper folding machine for use in a rotary press provided with a sheet delivery device.
The prior art paper folding device for use in a rotary press provided with a sheet delivery device comprises a cutting unit which cuts a web of printed paper into sheets of painted paper having a predetermined length, a folding device which folds the paper sheets and delivers folded paper sheets on a paper conveyor, (if necessary, the sheets are folded by a chopper) and a sheet delivery device which discharges the sheets in a stacked state. The folding device is constructed to discharge in different directions the sheet and folded sections, if desired.
The cutting unit comprises a cutting drum and a folding drum which are constructed to catch printed paper with needles of the folding drum to wrap the paper about the folding drum and to cut the paper into sheets having a predetermined length with a knife of the cutting drum when the paper has rotated a predetermined angle about the folding drum.
With such construction, however, when post printing the printed paper with a sheet-by-sheet rotary press for the purpose of printing catalogues or the like it is necessary to remove needle openings of the printed paper, that is to trim the paper for improving appearance. Furthermore, to fold the printed papers for binding books it is necessary to trim needle margins (usually 6 to 10 mm). As above described, even when the printed papers are discharged after folding or not folding, it is necessary to remove needle openings or needle margins in a succeeding step. For this reason, it is necessary to provide an additional cutting device.
Furthermore, in a prior art printing machine, since folded papers and unfolded papers are discharged in different directions, it is necessary to install a control device for aligning the cutting position with respect to the printed paper surface and to align printed colours, near the folding device or the paper delivery device thus requiring a large floor space.